Design of Optical Nor Logic Gates Using Two Dimension Photonic Crystals.

In this paper, a novel all-optical NOR logic gate based on two dimension (2-D) photonic crystals (PC) is designed and simulated by a cascade of two all-optical switches. The new all-optical switch is composed of a nonlinear photonic crystal ring resonator (PCRR) and T-type waveguide. The PC structure has a square lattice of silicon rod with refractive index of 3.39 in air. The bandgap of this structure is derived by the plane wave expansion (PWE) method, which is from a/= 0.32 to a/= 0.44. In this structure to work at the wavelength of 1550 nm, the lattice constant ‘a’ should be 630 nm; the total size of the proposed optical NOR gate is only 18 m × 11 m. The simulation results using two dimensional finite difference time domain (FDTD) method indicated that the proposed optical NOR logic gate is a potential candidature for ultrafast optical digital circuits.